Applies to: HDMI source and display with documented signal-range controls; use a correctly identified, lawful dark-detail reference.
The useful distinctions
- Sony documents automatic or fixed HDMI signal-range selection.
- Sony warns that incorrect range information can hide dark or bright detail.
- Diagnostic inference to test: A range-pairing comparison concerns the source/display interface, not original grading.
Establish a trustworthy reference
A deliberately dark scene cannot by itself tell you which details should be visible. Use a permitted reference with known intended steps or visible objects. Keep room lighting, display mode and brightness controls steady. Write down the source and display range states separately; an “auto” label at one end is not a direct measurement of what the other end sends.
Test the interface before compensation
The comparison asks whether a documented compatible pairing restores distinctions in the same image. Do not simultaneously increase brightness, contrast and gamma. That would make it impossible to tell whether the interface change mattered. If the source range is unknown or a control is absent, preserve that uncertainty instead of selecting a value copied from another device.
Keep the diagnosis bounded
A repeatable improvement supports investigating range negotiation or configuration in this HDMI path. It does not prove that every dark scene should reveal more detail or that the original creative grade is wrong. If the reference remains abnormal under a documented pairing, consider a display-side reference or manufacturer calibration guidance. A perceptually pleasing image alone is insufficient to certify accurate luminance reproduction.
A focused way to proceed
- Record the source output range and display input range without changing them.
- Show a known dark-detail reference with documented intended use.
- Compare only manufacturer-supported matching or automatic states.
- Inspect the same dark objects and restore the original pairing.
- Record whether detail changes while other picture controls stay fixed.
Worked example · synthetic
Hypothetical example: distinct dark reference steps merge in one recorded pairing and return in a documented compatible pairing, with brightness unchanged. The user reports an interface-dependent result, rather than claiming that every shadow in a programme must become visible.
When to stop or ask for help
Use exact device guidance and known reference provenance. This guide provides no universal numeric black-level or calibration target.